Fluid-pressure brake



C. C. FARMER FLUID PRESSURE BRAKE Aug. 21, 192s. 1,681,576

Filed oct.. v, 192e' CLYDE C. FARMER ATTORNEY EY I Patented Aug. 21', 1928.

UNITED STATESl y PATENT ,oi-"Fics,

CLYDE C. FARMER, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE WESTING- HOUSE AIR BRAKE COMPANY, OF WILMERDING, PENNSYLVANIA, A CORPORA- TION OF PENNSYLVANIA.

rLuIn-rimssnnn BRAKE.

Application filed October 7l, 1926. Serial No. 140,084.

This invention relates to fluid pressure brakes, and more particularly tomeaiis for retaining fluid under pressure in the brake cylinder, in the operation of releasing the brakes. i

In the running of railway trains, `when descending grades, it is desirable to retain fluid pressure in the brake cylinder when the brake pipe pressure is increased torelease the brakes, vso that the auxiliary reservoirs throughout the tiain may be recharged from the brake pi'pe,-without releasing the brakes. The principal object of my invention'is to provide means, under the control of' the engineer, whereby the brake cylinder pressure retaining means may be cut Vin when the train is descending a grade and cut out when the train is running on a leve-l. r`

In the accompanying drawing, the single figure is a view of a fluid pressure brake equipment, showing my invention applied thereto.

As shown in the drawing, thebrake equipopposite side of the diaphragm, contains a coil spring 9 which acts ona diaphragm follower 10 engaging the diaphragm, A valve 11 is contained in valve chamber 12 and provided with a stem 13, adapted to be engaged by a stem 14 carried bythe diaphragm follower 10.

The chamber 12 is connected by a pipe 15 to the usual exhaust port of the triple valve device land said chamber is also connected through a restricted port 16, with a valve chamber 17, containing a valve 18, adapted to control communication from valve chamber 17 to the atmosphere.

The valve 1S is operable by a flexible dia phragm 19, having a diaphragm follower 20 engaging the diaphragm at one side and said follower having a stem 21, adapted to engage the stem of valve 18. The chamber 22, at one side of the diaphragm 19, is connected by a passage 23 to diaphragm chamber 6y andis therefore subject to fluid at auxiliary reservoir pressure. A coil spring 211 is mounted in chamber 25,*at the '5, so as to open the valve 11 and when operating in level road service with a normal standard brake pipe pressure of 90 pounds, the diaphragm 5 will be operated to hold the valve 11 open and said valve will be held open in applying the brakes, even if the auxiliary reservoir pressure be reduced substantially to the equalizing point, pounds. i

With the valve 11 open, the brake cylinder exhaust port of the triple valve device 1 l is connected through pipe 15 and past the open valve 11 to an atmospheric exhaust port 26, and consequently, the 'brakesr will be released in the usual manner in releasing the brakes, withoutretaining fluid under pressure in the brake cylinder.

In operating on a grade, a lower standard brake pipe pressure YO pounds is carried and at thispi'essure, 'the diaphragm 5 perpheric exhaust port" 26" is cut ofl' from the brake cylinder exhaust pipe 15 and fluid from the rbrake cylinder can only exhaust through the `restricted port 16.

The spring 24acting on the diaphragm 19, is such that the auxiliary reservoir pressure in chamber 22 will be effective on diaphragm 19 to hold the valve 18 open, unless the auxiliary reservoir pressure is reduced to a very low degree, say less than 50 pounds, which pressure is the equalizing point when the standard brake vpipe pressure carried is 70 pounds. The valve 18 is there-` 'T'ore normally held open and in releasing the brakes in grade service, fluid will only escape from the brake cylinder at a rate corresponding with the size of the restricted port 16. As a. consequence, fluid under pressure is retained in the brake cylinder for a sulficient time to permit the auxiliaryv reservoir to' be recharged.

`mits the valvell to close, so that the atmos-A If the auxiliary reservo-ir pressure should fall below the pressure at which the spring 24: is adjusted, the diaphragm 19 will be operated to permit the valve 18 to seat. The fluid pressure, then in the brake cylinder, is thus retained and kWill not escape until the auxiliary reservoir pressure has been increased sufficiently to cause the diaphragm 19 to be operated so as to again open the valve 18.

In order to be able to cut the brake cylin-r4 der pressure retaining feature out of action, a cock 27 may be provided, having an operating handle 28. When it is desired to cut the retaining valve device out of action, the handle' 28 is operated to turn the valve 27,

so that port 29 connects chamber 12 With an atmospheric exhaust port 80. The brake cylinder exhaust pipe 15 is thenconnected directly to the atmosphere, so that the triple valve device will operate in the usual manner to exhaust iiuid from the brake cylinder to the atmosphere, whenl the brake pipe pressure is increased to eifect the release of the brakes. i

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is

1. In a fluid pressure brake, the combination with a triple valve device, a brake pipe,

andan auxiliary reservoir, of means for controlling the brake cylinder triple valve exhaust port and operated by auxiliary reservoir pressure to connect said exhaust port to an unrestricted atmospheric port When a unrestricted exhaust port, and a movable abutment subject to the opposing pressures of the auxiliary reservoir and a spring for operating said valve.

i In a luid pressure brake,the*combina tion with a triple valve device having the usual brake 'cylinder exhaust port, ya brake` pipe and auxiliary reservoir, of means having av chamber connected to said brake cylinder exhausty port, a valve for controlling 'communication from said chamber to an unrestricted exhaust port, and a movable abutinents'ubject to the opposing pressures of j the auxiliary reservoir and a spring for operatingsaid valve, .said chamber having a'restricted exhaust'port for venting fluid from said chamber at a restricted rate.

4. In afluid pressure brake, the combination with an auxiliary reservoir and a triple valve device havingy the usual brake cylinder exhaust port, of a valve device for controlling the exhaust ot iiuid through said exhaust port and having a. chamber with twoA exhaust ports, one of Which 'is restricted, a valve for controlhngthe other exhaust port, and a movable abutment'subject to the opposing pressures of theauxiliary reservoirA and a .spring :tor operating said valve.

5. In a iuid pressure brake, the combination'ivith an auxiliary reservoir and a triple valve device havingthe usual brake cylinder exhaust port, of a valve device for controlling the exhaust of iuid through said exhaust port and having a -chamber With tvvo exhaust ports, one ofvvhich is restricted, a valve forcontrolling the other exhaust port, a movable abutment subject-to rthe opposing pressures of the auxiliaiyreservoir and av spring yfor operating said valve, a second valve for controlling communication through saidrestricted exhaust' to the atmosphere, anda movable abutment subject to theoposinO' ressures yof the auxiliai reservoirk and a spring for operatingsaid valve. In testimony whereof I have hereunto set lmy hand.

` .ioLYDn c/FARMER. 

